Field of the Invention
The present invention relates to free-standing and other watercraft lifts and watercraft covers for use with watercraft lifts.
Description of the Related Art
The use of boat covers to protect boats is well known. A number of designs are currently known to perform this basic operation. Many boats have multi-section covers, often with one covering the bow section and another covering the aft section. The covers are typically shaped to cover at least portions of the three-dimensional shape of a boat and are manually spread out over the boat and then manually attached using snap or other fasteners. The bow section is attached with fasteners around the perimeter of the bow section especially when there is a bow opening. The aft section is attached to fasteners on the windshield, or in front of the windshield, as well with fasteners around the perimeter of the aft section. This common cover system has several negative aspects for the user. The large number of snaps or other fasteners used make the covers time consuming to install. The covers are often difficult to install after the material ages. The covers are large and awkward to store on-board. The covers can be dirty, and unpleasant to handle. The covers tend to lose shape, causing pockets of water, which further cause a loss of shape and pools of water. The covers do not cover a significant amount of hull surface surrounding the covers, and do not cover significant portions of the sides of the boat with which used, which causes fading in the sun and does not protect these areas from dirt. The covers provide no security, which makes the contents of the boat and the boat itself vulnerable to theft.
Several two-dimensional automatic cover designs are currently known. U.S. Pat. No. 3,549,198 uses a rotating arm to pull a flat cover over the top of a dump truck to secure the contents. This design would not be ideal for use with a boat lift since the cover is two-dimensional, non-adjustable and would be impractical to fit the three-dimensional shapes of various boat types with which the lift might be used. The torsional spring of the roller is also subject to over-tightening.
It is known to use a two dimensional cover design similar to U.S. Pat. No. 3,549,198 for application on a portable boat lift with a pontoon boat. Such a design does not provide protection to the sides of the boat. It also is more vulnerable to side wind, since it has exposed edges that catch the wind. Both designs use a roller fixed to the front, and a set of arms which pull the cover rearward like a window shade. This type of design is undesirable for an application on a boat, since the cover slides over parts of the boat, causing cover wear, and potential boat damage. The fixed cover in the front also blocks views and is not attractive since the roller remains visible at the front even when the cover is deployed. Pulling the cover from a fixed roller in the front also can cause damage to the cover and boat by dragging the cover on the boat. Further, the lift with the cover similar to that described in U.S. Pat. No. 3,549,198 does not provide any protection against operation of the lift when the cover is deployed, which can cause cover or boat damage, especially if installed on lifts that translate rearward when lowering, such as the lift of U.S. Pat. No. 5,908,264. Since the lift of this patent with the cover similar to U.S. Pat. No. 3,549,198 does not use the same remote control, another drawback is that the user is required to operate it separately from the automatic boat cover. It is also desirable to be able to manually adjust the cover when operating in case it is not seating correctly.
U.S. patents such as U.S. Pat. Nos. 4,019,212 and 6,786,171 describe a cover system that does not touch the boat. These systems have a fixed roof with structure and retractable sides that completely surround the watercraft. The tall sides of these systems block views and are more vulnerable to wind. For use on a free-standing boat lift, the fixed roof structure can make the lift vulnerable to tipping. Because of the fixed roof, these systems often require permitting and are highly regulated.
U.S. Pat. No. 4,019,212 is a device that attaches to a free-standing boat lift and lifts the cover off vertically. This design requires an external frame and overhead structure to lift the frame. The design is not conducive to covering the full sides of the watercraft. Since the cover still creates a shadow over the water when the boat is off the lift, this design would often be regulated as a canopy or covered moorage and not as a boat cover.
U.S. Pat. No. 8,911,174 solves the challenges above, but did not address some additional challenges. In U.S. Pat. No. 8,911,174 the starting and ending position of the roller is important for cover fit and cover storage position. In that patent, the starting and ending position of the swing arm is adjusted by moving the upper cylinder pivot position along the swing arm. This adjustment is complicated since an adjustment impacts both the forward and rear position at the same time. These adjustments are made underwater, making adjustments even more challenging.
The lift of U.S. Pat. No. 8,911,174 prevents lowering the boat with the cover on by using a hydraulic switching manifold that switches the operation from lift mode to cover mode, and will not switch to lift mode unless cover is fully off.
The U.S. Pat. No. 8,911,174 uses a torsion spring to roll up the cover and to apply tension on the cover, which is important for operating the cover in the wind. Since more cover tension can be perceived as beneficial, the operator can over tension the torsion spring and cause spring damage.
The automatic boat cover of U.S. Pat. No. 8,911,174 is costly, largely due to the hydraulic and control systems.
Applying U.S. Pat. No. 8,911,174 to a boat lift with a lifting cradle, lifted by cables, is challenging since the pivot position under the boat may limit minimum water depth. If the pivot position is raised, the loads applied to the swing arm get very high as the angle of the arm gets very shallow in the forward and rear positions.
The automatic boat cover of U.S. Pat. No. 8,911,174 uses a custom fit cover for the boat. The design of this cover is difficult for some boats that have protruding features such as antennas and/or fishing gear.